Method for conducting reactions in the presence of a solid material



1951 J. A. CROWLEY, JR

METHOD FOR CONDUCTING REACTIONS IN THE PRESENCE OF A SOLID MATERIAL Original Filed Oct. 14, 1944 5 Sheets-Sheet l INVENTOR.

NOV. 6, 1951 J CROWLEY, JR 2,574,247

METHOD FOR CONDUCTING REACTIONS IN I THE PRESENCE OF A SOLID MATERIAL Original Filed 00k. 14, 1944 3 Sheets-Sheet 2 IN VEN TOR.

Maw

NOV. 6, 1951 J CROWLEY, JR 2,574,247 7 METHOD FOR CONDUCTING REACTIONS IN THE PRESENCE OF A SOLID MATERIAL Original Filed Oct. 14, 1944 3 Sheets-Sheet} 42 er f 42 4 INVEN TOR.

J M g/ T transfer medium. Due to the difficulty of obtaining suitable heat exchange fluids which are stable at temperatures of 1000-'1200 F., for example, a large part of the solid material is main-' tained at somewhat lower temperatures during the entire regeneration. This is a disadvantage because generally the composition of the contaminant deposit changes as the regeneration progresses, and requires increasingly higher temperatures for its rapid combustion as the regeneration approaches completion. Often the temperatures required for complete and rapid removal of the last part of the contaminant are below those which will damage the solidmaterial but above those obtainable in the apparatus above described. Moreover although the combustion of a given contaminant might take place very rapidly at a temperature of 900 R,

for example, in those sections of the regenerator near the air inlet where the oxygen content of the gas was high, yet the reaction might be very slow at this temperature in other sections of the regenerator where the oxygen, having been partly used, is substantially lower in partial pressure. If, however, higher temperatures of the order say 1000-1100 F. could be provided in those latter sections of the regenerator high combustion rates would be obtainable there also.

In order to avoid the disadvantage of regenerators of the above type and also to provide higher total gas throughput capacity, regenerators and reactors have recently been provided which consist of a series of alternate reaction and heat exchange stages, the reactant gas being passed in: parallel through the reaction stages. The present invention differs in several respects from such multistage vessels and offers several advantages thereover. An important embodiment of the present invention involves the provision in a reaction vessel of a plurality of vertically spaced rows of combined heat transfer and gas handling elements extending horizontally across said vessel, so as to provide heat transfer surface within a portion of the reaction zone suflicient to permit control of the solid material temperature range while at the same time providing a large remaining portion of the reaction zone between said rows of elements wherein the reaction may proceed in the absence of proximate heat transfer surface.

A major object of this invention is the provision in a process for conducting thermochemical fluid reactions in the presence of a moving contact material of an improved method for supplying or withdrawing heat to the reaction zone and for effecting contact between the fluid reactant and contact material under optimum temperature conditions.

A particular object is the provision in a process for conducting a thermochemical fluid hydrocarbon reaction in the presence of a moving column of catalyst of an improved method for supplying or withdrawing heat to or from the reaction zone by means of the fluid reactant charge.

Another object of this invention is the provision of a combined heat transfer and gas handling element adapted for use in such an apparatus as the above.

Another object of this invention is the provision in a process for conversion of hydrocarbons in the gaseous phase in the presence of particle form solid contact mass materials, of a method and apparatus for controlling the gaseous reactant and solid material temperature within a narrow preferred range of temperatures through- 4 out the reaction zone and especially in the vicinity of the gas inlets to the reaction zone.

Another object of the invention is the provision in a process for regeneration of a contaminant bearing particle form solid contact mass material by the action of a combustion supporting gas, of a method and apparatus wherein sufllcient heat may be removed from the solid material in those sections of the regeneration zone wherein the regeneration gas is fresh to control the solid material temperature within predetermined limits throughout the entire regeneration zone without the requirement of proximate heat transfer surfaces in those sections of the regeneration zone wherein the combustion supporting gas is relatively spent.

These and other objects of this invention will become apparent from the following description of this invention. Before proceeding with said description certain terms used herein should be defined. The term gas" or gaseous material as used herein and in the claiming of this invention are intended to cover any material in the gaseous phase at the temperature of the operation or reaction regardless of its normal phase at atmospheric temperature. The words "tube" or tubes are intended as covering not only circular conduits but conduits of any other contour.

Referring now to the drawings. Figure 1 is an elevational view, partially in section, showing a reaction vessel constructed according to this invention. Figure 2 is a vertical sectional view taken along line 2-2 in Figure 1, Figure 3 is an enlarged sectional view of one of the combined heat transfer and gas handling elements used in the apparatus of Figure 1, Figure 4 is a sectional view of a modified form of such an element, Figure 5 is an elevational view, partially in section, of a vertical section of a vessel which embodies a preferred modification of this invention adapted for catalyst regeneration, and Figure 6 is a similar view of another preferred modification of this invention adapted especially for hydrocarbon conversion and Figure 7 is a cross-sectional view of a modification in the construction of the vessel shown in Figure 6, taken at line 'l-I of Figure 6. All of these drawings are highly diagrammatic in form.

Turning now to Figure 1, we find I0 is the outer shell of a vertical reaction vessel which may be circular or rectangular in cross-sectional contour, II is the inner shell thereof and I2 is a layer of insulating material between the two shells. The shell I0 is closed on its upper end by the converging section [3 and on its lower end by converging section I4. An inlet conduit l5 for solid material is connected into the upper section l3 and an outlet conduit I5 having throttle valve ll thereon is depended from the lower section I4. A plurality of vertically spaced rows of 'horizontally spaced and horizontally extending tubes l8 and I9 extend across the vessel and through the opposite walls thereof. Two similar fins are attached as by welding along the length of each tube on either side thereof and extend downwardly and outwardly therefrom, so as to provide a solid material-excluding gas space extending along underneath each tube. The fins 20 on tubes [8, which join alternate rows, terminate within the vessel short of the outer shell on one end and plates 22 are provided across the ends of each set of fins on each tube. These fins extend through the vessel shell on the opposite end into the gas outlet manifold box 24 which is attached along the shell, thus communicating each alternaterow of gas spaces joined by tubes' I8 and fl'nsilfl with a gasoutletmanifbld-boi; 'Ihefin arrangement onthe remaining alternaterow' IQ'Of'tubes-is similar to that above described except that the fins terminate within the vesseland are provided with end plates 23 on the-oppo-- site end and extend through the opposite wall of the vessel into gas inlet manifold bo'xes 25- which extend horizontally across the shell and are attached thereto by flanges 26;

The arrangement may be more cIear-Iyunde'rstood by reference to Figure 2' which is asectional view along line 22 of'Figure- 1 and inwhich-like members bear like numeralsg- It will be seen from Figure 2 that the tubes. l 9 are' &- Set horizontally so asto-lie in thevertical-plane between adjacent tubes l8'in' the-rows above and below. In the vessel shown, the cross-section was such as to require four tubessome rows and only three in others, in-order toprovide uniform tube and fin distribution across the vessel. cross-section. The inventionis not to be limited, however, to such proportion. It will also benoted that the outside fins, on the end tubes in the rows containing four tubes, extend substantially vertically downward.

Turning again in Figure 1, the rows of'tubes terminate on one end in horizontal outlet headers 21, which are provided for each row, and on their opposite ends in horizontal inlet headers 23', also provided for each row. The outlet headers are interconnected by-riser pipes 29 to the lowermost of which is connected the main outlet cone duit 3D; and the inlet headers are interconnected by riser pipes 3| tothe lowermost of which is connected the main inlet conduit 32. Similarly, the gas inlet manifold boxes25 are interconnectedby riser pipes 33 to the lowermost of which is connected the main gas inletconduit 34, andthe outlet manifold boxes 24 are interconnected by riser pipes 35 to the lowermost of which the main gas outlet pipe 36 is connected.

In operation particle form solid material at the desired reaction temperature enters theves--- sel through conduit l5 and passes downwardly therethrough as a substantially compact column; The solid material is preventedfrom channeling downwardly in any given vertical path bythe staggered arrangement of the alternate rows of tubes and fins. Contacted solid material is withdrawn from the lower end of the vessel through conduit It, the rate of withdrawal being controlled by throttle valve I'l. Gasiform reactants at-the desired reaction temperature enter throughconduit 34 and riser pipes 33' into the several: inlet manifold boxes 25. The gas is then distributed into the several vertically spaced rows of gas spaces provided by tubes l9 and fins 20. From these gas distributing spaces thereactant gas passes upwardly and downwardly through the solid material toward the nearest rows of gas collecting spaces formed bytubes IS andfins 20; The gas then disengages from the solid material and collects in these latter gas spaces and passes therefrom into outlet manifold boxes- 24 and then through pipes 35' to the main gas outlet conduit 33. There are thus provided a series of superimposed reaction zones wherein-thevertical direction of gas flow is opposite-insucc'essive zones. The solid material temperatureis controlled by supply of a heat-exchangefluid through conduit 32, riser pipes 3i and manifolds 28 to the heat transfertubes I8 and! 9-. The heat. exchange fluid passes from the opposite ends of the-tubes into manifolds'flg and thencethrough sol-id material temperatureis-adjusted at a pl rality of levels along the vessel; by indirect heat transfer with aheatexchangefluid, the=temperatu-re adjustment-being. sufiicient at each-level-to prevent the solid material temperature from ris ing or falling beyondapredetermined limit duri'n'g its passage between heat exchange levels;- such: arr-apparatus when used for a hydrocar bon conversion process per-mits very high reac tant throughput capacityand permits accurate control of the reaction temperature throughout thereactionzone and especially during. the.ini.- tial-and finalinterval of the gaseous reactant. contactwith the solidimaterial while-atthe same; time a major. portionof the reactant flow. through. the: column is in the absencelof. indirect. heat; transfer; Such temperature. control notonly. re.- duces the amount of contaminant deposittoxa: minimum. but also. permits.- optimum. conversion. yields andproduct properties. a

The; combined; heatitransfer and gas. handlingelement permits a. substantial reduction in. the: total metal required within. the conversion VeSr'. sel, Thisisapparentxwhen it is considered that on. the. one. hand. thefins which define the. gas. distributing and collecting spaces also. serveas; additionalheat transferqsurfaces thereby reducing the: total number of heat transfer tubes req-uired; while .on. the. other: hand, the heat trans.- fer. tubesserve both. to; help definethe gas distributing: and collecting spaces and also tosupport the fins. Figure 3 isan enlarged. sectional. view;- showing. the: construction of. the combined heat transfer element. and. gas handling elements. used-in thewapparatus. ofFigurel; like numeralsare-used for like member. In. some. operations: larger. gasspaces aredesirablein which casethe fin shape and size maybe varied. Such a modified form is shown inFigure 4. In:Fig11re4, the element is comprised of a circular tube 38 and: tw'o angle shapedfins' 39, one weldedsalong eitherj side or the tube- When tubes of relatively large; diameter are employed, finsattached along their;

. sidesand extendingrsubstantially vertically. down? ward may be used. Moreover, if. desired, tubes: ofi'cross-sectional.shapes other thancircular may: be-used- Insome. modifications, it may be. de-. enable to interconnect the ends ofadjacent tubes: in eachrow so asto provide a continuous coil for heat exchange fluid fiow in each row of tubes" Such a modification is particularly desirable. when a relatively great change in the temperature oithe heat exchange fluid is desired.

In some-applications of the invention theuse. of heat transfer tubes atboth the levels of gas inlet and gas outlet is not necessary. Such amodification is shown in Figure 5 wherein shown avertical view, partially in section, of .a. vertical section of a vessel adapted for either endothermic or exothermic reactions, and par-- ticularly well adaptedfor useas a catalyst regen erator. Thevessel is generally the same type asthatshown in Figure 1 except for internal modi- 1 fications as described'hereinafter. In Figure 5, 40'

represents 1 the outer shell of the vessel, 4| the inner shell and 42 the insulator therebetween. Heat transfer tubes 43- having fins 44 attached along their length are provided in a plurality ofvertically spaced rowsacross the-vessel. Theseelements-serve ascombined gas inlet distributing and heat transfer elements similarly to those; shown in-Figures- 1 and2, gas-inlet manifold boxes- 45 being provided along one side ofthe vessel shell: A maingas inlet riser pipe 46 is provided" 7 from which gas is distributed through pipes 41 having valves 48 thereon into the several inlet manifold boxes. Intermediate the rows of combined heat transfer and gas distributing elements, rows of inverted angle shaped troughs 49 are positioned across the vessel. These channel mem bers are closed on either end and terminate within the vessel short of the external shell. These channels serve as gas collectors and gas is removed therefrom through pipes 50 which extend through the vessel shell and a short distance under the collectors on one end and each of which pipes 50 is connected into the gas outlet duct on theopposite end. The heat transfer tubes connect on their inlet ends into inlet manifolds 52 which are interconnected through pipes 53; and the heat transfer tubes are connected on their outlet ends into manifolds 54 which are interconnected through the outlet riser pipes 55. The construction is thus such as to divide the regenerator into a series of superimposed stages wherein the gas flow is alternately vertically upward and downward through the solid material column flowing therethrough. The solid material temperature is adjusted only in that section of the vessel in the immediate vicinity of the gas inlets in which section the regeneration gas, for example, air, is fresh. Thus the solid material in passing by a given row of heat transfer tubes may be cooled from a temperature of 1 50 F. to a temperature of 900 F. and may then be heated in the section of the regenerator between the rows of tubes back to 1150 F. by the heat liber-r.

ated by contaminant combustion. The air charge may be supplied into the distributing elements at a temperature near that of the column at the level of inlet, i. e. about 850-950 F. The temperature of the solid material passing by the gas collectors where the air is relatively spent may be of the order of 1025 F. Thus, by permitting the combustion reaction to proceed at a somewhat higher temperature and in the absence of proximate heat transfer surfaces in those sections of the regenerator wherein the air is relatively spent than in those sections wherein the air is fresh, a high and uniform rate of contaminant combustion is provided throughout the regenerator resulting in higher overall burning capacity and efficiency. When the system described above is used for a hydrocarbon cracking reaction, heat is supplied to the catalyst through tubes 43 so as to heat the catalyst at the levels of initial hydrocarbon contact with the catalyst to the optimum conversion temperature. The oil charge is preheated in an external heater (not shown) which may be of conventional construction and is supplied into the column substantially at the column temperature at the levels of initial contact. For example, in cracking a mid continent gas oil boiling within the range about 450-800 F. in the presence of a silica-alumina clay type catalyst, the catalyst may be heated to about 850 F. at each level of oil inlet. The catalyst temperature may fall off between the rows of heat transfer tubes about 5-30 F. depending upon the spacing of the tubes and the reaction conditions. The oil charge is introduced at about 850 F.

In general, it is important that the reactant charge enter the contact material column within about 50 F. plus or minus of the contact material column at the points of initial contact and preferably within at least 25 F. thereof. In some operations the catalyst temperature may be varied at the different levels of heat transfer tubes. For examp e. i a hy ro arbon cracking c n s n process the catalyst and oil inlet temperature may be progressively increased at successively lower levels or groups of levels along the reaction zone so as to counteract the loss in catalyst activity due to contaminant deposition thereon.

Another modification of the invention particularly adapted for hydrocarbon conversion is shown in Figure 6 which is a vertical view, partially in section, of a vertical section of a reactor. This vessel may be of the same general construction as that shown in Figure 1, except for internal modifications as shown and except for provision for sealing either end of the vessel with an inert gas, which provision is now conventional and not shown. Within the vessel shown in Figure 6 are positioned a plurality of vertically spaced rows of tubes 60 which extend through the inner shell BI and outer shell 62 of the vessel on opposite ends, one end of the tubes in each row connecting into the horizontal inlet manifolds 63 and the opposite open end terminating within the closed header box 64 which is attached horizontally along the outer vessel shell adjacent the row of tubes. Fins 65 are attached along the tubes 60 similarly to those shown heretofore, each pair terminating within the vessel on one end, said end being closed by plate 66, and terminating within the header box 64 on the opposite end. Also positioned within the vessel are vertically spaced rows of tubes 61 located intermediate the rows of tubes 60. As has been mentioned hereinabove in some operations such as the hydrocarbon conversion operation just described, it may be desirable to connect the adjacent ends of the tubes of each row thereof to provide in each row a continuous coil. Such an arrangement is shown in Figure 7 which is a cross-sectional view of an apparatus similar to that in Figure 6 taken at a level just above and looking down on a row of tubes 60 except that while in Figure 6 the heat transfer tubes are arranged for parallel flow of inlet reactants, in Figure '7, the tubes 60 are arranged for series flow of reactants. Thus, the proper ends of the adjacent tubes 61 are connected together by means of U-bends so that reactants enter one of the end tubes from manifold 9| through valve 94 and pass' serially through the tubes to issue from the open end of the end tube on the opposite side of the vessel into header box 64 which extends horizontally across the outside of the vessel shell 62. header box 92 and passes therefrom under the gas distributing spaces formed by fins 65 which distributing spaces are in free gas flow communication with the interior of header box 64. This arrangement is particularly desirable when the heat of reaction is high requiring substantial superheat in the reactant entering the coils. In such case a single tube will not provide sufficient heat transfer surface to permit cooling of the oil charge to the catalyst column temperature and it is important in such cases to pass the oil charge through a sufficient number of tubes to insure cooling thereof to a level near that of the catalyst before permitting it to contact the catalyst.

It will be understood that this invention i considered to be broadly applicable to many thermochemical reactions other than those specifically mentioned herein. For example, it may be employed for hydrocarbon polymerization, oxidation, dehydrogenation, and reforming reactions and for hydrocarbon synthesis reactions.

I claim:

1. A method forconducting thermochemical The vapor then distributes throughout conversions involving-a reactant-fluid-inthe prestends to change dueto said thermochemical conversionwhich method comprises passing a particle form solid contact mass material through an elongated conversion zone; the contact material moving directly through said zone without substantial reversal in its general direction of flow therethrough, adjustingthe temperature of said contact material by'indirect heat transfer at a plurality of spaced apart intervals along'its path of flow, said adjustment intemperature being'in' a direction opposite to the contact material change in temperature due to said thermochemical conversion, introducing reactant fluid" intosaid conversion zoneintocontactwith said con-- tact material at'a plurality of spaced: apart locations each one of; said locations of'reactantintroduction being near and immediately downstream of a separate one of; saidintervals of indirect heat transfen whereby the reactant fluid initially condifferent from the temperature at the location of" reactant introduction, and withdrawing fluid'reactants from said; conversion zone at a second plurality of intervals along the. path of solid material flow substantially spaced apart from said intervals of heat transfer.

2. A method for, conducting thermochemical conversions involving a. reactant fluid within a narrow range of optimum conversion temperatures in the presence of a particle form solid contact material wherein the contact material temperature tends to stray from said narrow range of optimum temperatures due to said thermochemical conversions which. method comprises, passing a particle form solid contact material through an elongated conversion zone as a substantially compact gravitating column, adjusting the temperature of said. contact material by indirect heat transfer at a plurality of vertically spaced apart intervals within the conversion zone, said adjustment in temperature being in a direction opposite to the stray in temperature dueto said thermochemicalconversion whereby the contactmaterial is controlledsubstantially at the optimum conversion temperature at each of said intervals of indirect heat transfer, introducing reactant fluid feed into said conversion zone at a plurality of spaced apart levels along its length which are located only near and immediately below intervals of indirect heat transfer, whereby the reactant initially contacts only contact material which has just been adjusted t the desired conversion temperature, controlling the inlet temperature of said reactant fluid so that it exists within at least about 50 F. of the contact material temperature at the instant of initial contact whereby the fresh reactant fluid feed is converted to fluid products under optimum temperature conditions, flowing the reactant fluid introduced at each level through a separate vertical portion of the column length along a substantial p r Of hich the fl w is in the absence of indirect heat transfer and thecontact material'tempera-- ture is substantially diiierent from its temperature at the level of reactant introduction and withdrawing fluid reaction products from said conversion. zone at a second plurality of levels along the said conversion zone substantially spaced apart from said levels of reactant introduction.

3; A method for conducting thermochemical conversions involving a reactant fluid within a narrow range of'optimum conversion tempera-- tures in the presence of a particle form solidi contact material. wherein the contact material temperature tends to stray from said narrow range of optimum temperatures due to said'th'ermochemical conversion which method comprises, passing a particle form solid contact material downwardly through a series of communicating reaction zones in which it flows as a substantially compact column, introducing a gasiformreactan-theated to suitable reaction temperature into each of said zones and passing it vertically through the column ofcontact material therein to effect" the thermochemical conversion of said reactant to a gasiform product whereby the contact mate rial temperature is changed as it flows along saidzones due to said thermochemical conversion, withdrawing the gasiform product from eachof said zones at a level vertically spaced from the level of reactant introduction and adjusting the temperature of said-contact material toa level" near that of the reactant inlet temperature t'off said zones by-indirect heat transfer only at locations' in said column immediately above the levelsof reactant introduction to and withdrawalfromf said column in said zones whereby the reactant flowingin each zone undergoes conversion-in a;

portion thereof in the presenceof indirecthat transfer and in a separate portion thereof in' the absence of indirect heat transfer and at a substantially different temperature from that in the portion of indirect heat transfer.

4; A method for conducting thermochemica l conversions involving a reactant fluid within a1 narrow range of optimum conversion temperatures in the presence of a particle form solid con j tact materialwherein the contact materialtemaperature tends to stray from said narrow range 5 of optimum temperatures due to said thermochemical conversion which method comprises passing a particle form solid contact material through a series of communicating conversion zones, the contact material moving directly through each zone without substantial reversal in itsgeneral direction offiow therethrough, sep'- arately introducing reactant fluid, heated to, optimum. temperature level foroeifecting saidi' conversion into each conversion zone, passing the reactant fluid through each conversion zone to effect its conversion whereby the temperature of the contact material tends to change due to the thermochemical conversion, withdrawing reaction products from each conversion zone at a point along the path of solid flow substantially spaced apart from the point of reactant introduction, and adjusting the temperature of the contact material in each of said zones in the immediate vicinity of reactant introduction thereto and immediately before itrreaches the point of reactant introduction by means of indirect heat transfer while excluding indirect heat transfer from the intermediate portion of each zone lying between the points of reactant introduction and withdrawal, said adjustment being in a direction opposite to the contact material temperature change due to said thermochemicalconversion and being sufficient to provide a contact material temperature .in the immediate vicinity of reactant introduction into each of said zones which is substantially different from. its temperature in said intermediate portion of said'zone and which is near said optimum conversion temperature level at which the reactant is introduced;

5. A method for conducting endothermic cracking conversions of high boiling fluid hydrocarbons to lower boiling hydrocarbon products in the presence of a particle form solid contact material which comprises passing a particleform solid contact material substantially unidirectionally through a series of communicating conversion zones, introducing high boiling hydrocarbon feed heated to the desired conversion temperature into each of said conversion zones to initially contact said contact material existing near the. inlet temperature of the hydrocarbon feed and applying heat to the contact material byindirect heat transfer upstream in the contact material flow but in the immediate vicinity of the location of hydrocarbon introduction into each of said zones to maintain the contact material near the hydrocarbon inlet temperature and desired reaction temperautre as aforesaid, passing the hydrocarbon feed introduced into each zone while still in contact with the solid material through a subcontact mass material through an elongated reaction zone, the solid material being moved directly through said zone without substantial reversal in its general direction of flow therethrough, passing gasiiorm hydrocarbon charge, superheated above the desired conversion temperature in indirect heat transfer relationship with said moving solid contact material at a plurality of spaced intervals along its path of flow to sub stantially supply the heat for the endothermic hydrocarbon conversion thereto, passing the gasiform hydrocarbon conversion charge, after being cooled during said indirect heat transfer relation-- ship to a temperature near that of said contact material, into direct contact with the flowing solid material adjacent and immediately downstream of said intervals of heat transfer, flowing the 12 gasiform hydrocarbons through'a substantial portion of said zone which is maintained in the absence of the direct influence of said indirect heat transfer and in which the contact material temperature is substantially below its temperatureat the locations of hydrocarbon introduction, and finally withdrawing gasiform conversion products from the reaction zone at a second plurality of intervals along the path of solid material flow spaced apart from said intervals of heat transfer.

7. A method for conversion of gasiform hydrocarbons in the presence of a moving particle form solid contact mass material at controlled elevated temperatures comprising passing a particle form solid contact mass material as a substantially compact column of downwardly flowing solid material through a confined conversion vessel, passing gasiform hydrocarbon charge superheated above the desired conversion temperature but below the temperature of substantial thermal conversion in indirect heat transfer relationship with saidcolumn of solid material at a plurality of vertically spaced levels to continually adjust the flowing solid material to the desired limiting range of hydrocarbon conversion temperatures while said hydrocarbon charge is cooled to said limiting range of conversion temperatures before it comes into contact with the solid material, then passing the cooled hydrocarbon charge into the solid material column at a plurality of levels immediately below said levels of indirect heat transfer, flowing the hydrocarbon charge introduced at each level through a separate substantial portion of said column in the absence of proximate indirect heat transfer, the temperature in said last namedportion being at a substantially lower conversion level than at the level of hydrocarbon introduction, withdrawing gasiform conversion'produc'ts from said column of solid material at a second plurality of levels intermediate said levels of heat transfer.

JOHN A. CROWLEY, JR.

REFERENCES orrEn The following references are of record in the flle of this patent:

UNITED STATES PATENTS 

1. A METHOD FOR CONDUCTING THERMOCHEMICAL CONVERSIONS INVOLVING A REACTANT FLUID IN THE PRESENCE OF A PARTICLE FORM SOLID CONTACT MASS MATERIAL WHEREIN THE CONTACT MATERIAL TEMPERATURE TENDS TO CHANGE DUE TO SAID THERMOCHEMICAL CONVERSION WHICH METHOD COMPRISES PASSING A PARTICLE FORM SOLID CONTACT MASS MATERIAL THROUGH AN ELONGATED CONVERSION ZONE; THE CONTACT MATERIAL MOVING DIRECTLY THROUGH SAID ZONE WITHOUT SUBSTANTIAL REVERSAL IN ITS GENERAL DIRECTION OF FLOW THERETHROUGH, ADJUSTING THE TEMPERATURE OF SAID CONTACT MATERIAL BY INDIRECT HEAT TRANSFER AT A PLURALITY OF SPACED APART INTERVALS ALONG ITS PATH OF FLOW, SAID ADJUSTMENT IN TEMPERATURE BEING IN A DIRECTION OPPOSITE TO THE CONTACT MATERIAL CHANGE IN TEMPERATURE DUE TO SAID THERMOCHEMICAL CONVERSION, INTRODUCING REACTANT FLUID INTO SAID CONVERSION ZONE INTO CONTACT WITH SAID CONTACT MATERIAL AT A PLURALITY OF SPACED APART LOCATIONS EACH ONE OF SAID LOCATIONS OF REACTANT INTRODUCTION BEING NEAR AND IMMEDIATELY DOWNSTREAM OF A SEPARATE ONE OF SAID INTERVALS OF INDIRECT HEAT TRANSFER, WHEREBY THE REACTANT FLUID INITIALLY CONTACTS ONLY CONTACT MATERIAL WHICH HAS BEEN RECENTLY ADJUSTED TO AND IS AT THE DESIRED CONVERSION TEMPERATURE, MAINTAINING THE TEMPERATURE OF SAID REACTANT FLUID JUST PRIOR TO INITIAL CONTACT WITH THE CONTACT MATERIAL NEAR THAT OF THE CONTACT MATERIAL AT SAID LOCATIONS OF REACTANTS INTRODUCTION, FLOWING THE REACTANT FLUID INTRODUCLOCATION THROUGH A SEPARATE VERTICAL PORTION OF SAID CONVERSION ZONE, ALONG A SUBSTANTIAL PART OF WHICH THE FLOW IS IN THE ABSENCE OF INDIRECT HEAT TRANSFER AND THE TEMPERATURE AT THE LOCATION OF DIFFERENT FROM THE TEMPERATURE AT THE LOCATION OF REACTANT INTRODUCTION, AND WITHDRAWING FLUID REACTANTS FROM SAID CONVERSION ZONE AT A SECOND PLURALITY OF INTERVALS ALONG THE PATH OF SOLID MAINTERVALS OF HEAT TRANSFER. 